JP2011001413A - Resin composition and method for producing the same - Google Patents

Abstract

A transparent resin composition having excellent heat ray shielding property, a method of manufacturing the same, and provides a molded article comprising the resin composition.
A resin composition containing polyvinyl alcohol and zinc antimonate, wherein the zinc antimonate is dispersed with an average particle size of 60 nm or less in the resin composition, and its production A method and a molded article comprising the resin composition.
[Selection figure] None

Description

  The present invention relates to a resin composition excellent in transparency and heat ray shielding properties, a method for producing the same, and a molded article made of the resin composition.

  In recent years, as one of the purposes for energy saving, the use of so-called heat ray shielding materials that reflect or absorb near-infrared rays on the windows of buildings and vehicles is increasing. In particular, it is desired to efficiently shield the heat rays in the wavelength range of 780 to 2100 nm, which are considered to be related to the sensation of sensation and the thermal sensation. On the other hand, transparent organic polymer materials are widely used in various fields such as lens materials in the electronic and electrical equipment fields, optical equipment fields, and carport roof materials in the building materials field, taking advantage of their light weight. For the purpose of imparting heat ray shielding properties to these materials, resin compositions using organic substances that are easily mixed with resins have been proposed. For example, a method of blending a phthalocyanine compound as a near-infrared absorbing material has been proposed, but organic materials have a problem of durability such as poor weather resistance and a loss of effect in long-term use.

  On the other hand, a method of sticking a heat ray reflective film formed by sputtering or vapor deposition of a metal thin film such as aluminum, silver, gold or the like on the surface of a transparent film substrate (for example, see Patent Document 1) is disclosed. Yes. However, although the metal sputtering thin film and the vapor deposition film are excellent in heat ray shielding performance, they are poor in transparency. Therefore, when used by being attached to a window glass, the visible light transmittance of the window is impaired and the metal is used. Since there are also gloss reflections, there are disadvantages such as being unfavorable in appearance, inevitable that the manufacturing cost is high, and possibly affecting radio wave characteristics.

  Therefore, heat ray shielding films containing tin-doped indium oxide (ITO) fine particles or antimony-doped tin oxide (ATO) fine particles having heat ray shielding properties have been proposed (see, for example, Patent Documents 2 and 3). However, the use of ITO has problems of resource depletion and price increase. Recently, it has also been reported that ITO fine particles adversely affect the human body (see Non-Patent Document 1). On the other hand, the use of ATO has problems such as insufficient performance.

  On the other hand, a heat ray shielding film using zinc antimonate has been proposed as an alternative to the fine particles having heat ray shielding properties. Patent Document 4 describes that a powder of zinc antimonate is dispersed in water or an organic solvent and then mixed with various resins. However, when manufactured by such a method, the primary particle diameter of zinc antimonate is 10 to 50 nm, but in the dispersion or resin, the primary particles are in a secondary aggregated state. It was inevitable that haze was deteriorated due to scattering, and could not be used in applications requiring high transparency. Although it is also described that the zinc antimonate is treated with a silane coupling agent, the surface modification of the anhydrous zinc antimonate is low and the surface modification does not proceed sufficiently. Transparency was insufficient.

  Furthermore, polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) is one of the transparent organic polymer materials as described above. PVA transmits visible light and has high transparency. There was a problem that heat ray shielding was inferior. In order to solve this problem, a carrier tape in which PVA is used as a binder and mixed with zinc antimonate has been studied (Patent Document 5), but the dispersion state is not sufficient, and light is scattered under visible light, resulting in deterioration of haze. This is unavoidable and cannot be used in applications where high transparency is required.

JP-A-57-59749 JP-A-8-281860 JP-A-9-108621 Japanese Patent Laid-Open No. 9-212221 JP 2007-137432 A

J. et al. Aerosol Res. , 20 (3), 213-218 (2005)

  This invention is made | formed in order to solve the said subject, and it aims at providing the resin composition excellent in transparency and heat ray shielding. It is also an object of the present invention to provide a method for producing such a resin composition and a molded body comprising the same.

  The present inventors have intensively studied to achieve the above-described object. As a result, the above-mentioned problem is a resin composition containing polyvinyl alcohol and zinc antimonate, wherein the zinc antimonate is dispersed in the resin composition with an average particle diameter of 60 nm or less. Solved by providing. At this time, the visible light transmittance in the wavelength region 380 to 780 nm measured according to JIS R3106 is 70% or more, the solar transmittance in the wavelength region 300 nm to 2500 nm is 80% or less, and according to JIS K7105. The measured haze is preferably 4.0 or less.

  Furthermore, the above-mentioned problems can be solved by providing a method for producing a resin composition characterized in that a dispersion of zinc antimonate is subjected to a wet pulverization treatment and then mixed with polyvinyl alcohol. Moreover, it is solved also by providing the molded object which consists of said resin composition.

  According to the present invention, it is possible to provide a resin composition excellent in transparency and heat ray shielding and a molded product thereof. Moreover, according to the manufacturing method of this invention, such a resin composition can be manufactured by a simple method.

Hereinafter, the present invention will be described in detail.
The resin composition of the present invention contains PVA and zinc antimonate.

  The PVA used in the present invention can be produced by saponifying a polyvinyl ester polymer obtained by polymerizing a vinyl ester.

  Examples of vinyl esters include vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl versatate, vinyl laurate, vinyl stearate, vinyl benzoate and the like. Among these, vinyl acetate is preferably used from the viewpoints of availability, ease of production of PVA, cost, and the like.

  The above PVA is not limited to a saponified product of a homopolymer of vinyl ester, and unless the effect of the present invention is impaired, the copolymer of vinyl ester and a small amount of other copolymerizable monomers. It may be a saponified product (sometimes referred to as modified PVA), polyvinyl acetal in which a part of the hydroxyl group of PVA is cross-linked, or the like.

  Other copolymerizable monomers that can be used for copolymerization with vinyl esters include, for example, α-olefins having 2 to 30 carbon atoms such as ethylene, propylene, 1-butene, and isobutene; (meth) acrylic Acids and salts thereof; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, (meth) acrylic (Meth) acrylates such as i-butyl acid, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate; ) Acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, dia (Meth) acrylamide derivatives such as ton (meth) acrylamide, (meth) acrylamide propanesulfonic acid and salts thereof, (meth) acrylamidepropyldimethylamine and salts thereof, N-methylol (meth) acrylamide and derivatives thereof; N-vinylformamide N-vinylamides such as N-vinylacetamide and N-vinylpyrrolidone; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether , Vinyl ethers such as stearyl vinyl ether; nitriles such as acrylonitrile and methacrylonitrile; vinyl chloride, vinylidene chloride, vinyl fluoride, fluoride Vinyl halides such as vinylidene; allyl compounds such as allyl acetate and allyl chloride; maleic acid and its salts or esters thereof; itaconic acid and its salts or esters thereof; vinylsilyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; Saturated sulfonic acid etc. can be mentioned. These copolymerizable monomers can be used alone or in combination of two or more.

  Examples of the polyvinyl acetal in which a part of the hydroxyl group of PVA is crosslinked include polyvinyl acetal in which a part of the hydroxyl group of PVA is crosslinked with aldehydes such as formalin, butyraldehyde, and benzaldehyde.

  The degree of polymerization of PVA used in the present invention is preferably 1000 or more, more preferably 1300 or more, and even more preferably 1500 or more. There exists a possibility that a moldability may worsen that the polymerization degree of PVA is less than 1000. Although there is no restriction | limiting in particular as an upper limit of a polymerization degree, Since manufacture of PVA is industrially difficult, it is preferable that it is 10,000 or less, 8000 or less is more preferable, and 6000 or less is still more preferable. In addition, the polymerization degree of PVA as used in the field of this invention means the polymerization degree measured according to JIS K 6726.

  The saponification degree of PVA is preferably 97 mol% or more, more preferably 97.5 mol% or more, and even more preferably 98 mol% or more, from the viewpoint of water resistance of the obtained PVA film. When the saponification degree of PVA is less than 97 mol%, the water resistance of the obtained PVA film may be deteriorated. The degree of saponification of PVA is actually the total number of moles of units (typically vinyl ester units) that can be converted to vinyl alcohol units by saponification among the structural units constituting the polymer. The ratio (mol%) of units saponified into vinyl alcohol units. The degree of saponification of PVA can be measured according to the method described in JIS K 6726.

  The resin composition of the present invention contains zinc antimonate in order to impart heat ray shielding properties. The zinc antimonate used in the present invention is a mixed oxide composed of anhydrous zinc antimonate containing a zinc oxide component and an antimony oxide component. In the mixed oxide, the component ratio of antimony oxide to zinc oxide is preferably 0.8 to 1.2 in terms of molar ratio. The content of zinc antimonate is preferably 10 parts by weight or less, more preferably 6 parts by weight or less with respect to 100 parts by weight of PVA from the viewpoint of transparency and fine dispersion. On the other hand, it is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more with respect to 100 parts by weight of PVA from the viewpoint of heat ray shielding.

  Zinc antimonate needs to be finely dispersed in the resin composition. If not finely dispersed, light is scattered under visible light and haze increases. In general, when the content of zinc antimonate is the same, it is known that when the particle diameter is reduced to 1/100, the distance between particles is reduced to 1/100 [for example, the world of nanocomposites, p22. (See Industrial Research Committee)]. On the other hand, when zinc antimonate particles are aggregated in the resin composition, the distribution of the particles can be made dense, and there are places where heat rays are shielded and penetrated, resulting in a decrease in heat ray shielding performance. . According to the study by the present inventors, when zinc antimonate is dispersed in fine particles having an average particle diameter of 60 nm or less in the resin composition, the zinc antimonate is in a dense state in the resin composition. Shielding performance is improved. In other words, the PVA resin composition of the present invention can effectively impart heat ray shielding performance with a small amount of fine particles of zinc antimonate due to this nano-size effect. The average particle diameter in the resin composition of zinc antimonate is more preferably 50 nm or less.

  In order to disperse zinc antimonate with an average particle diameter of 60 nm or less, a surface modifier can be added to the resin composition of the present invention as necessary. The surface modifier is not particularly limited and is generally used as a dispersant, an emulsifier, an antifoaming agent, a lubricant, a penetrating agent, a cleaning agent, a builder, a hydrophobizing agent, a surface conditioner, or a viscosity conditioner. Examples thereof include nonionic surfactants, cationic surfactants, anionic surfactants, amphoteric surfactants, polymer dispersants, and coupling agents.

  In addition, the resin composition of the present invention includes various additives as necessary within a range that does not impair the effects of the invention, such as plasticizers, antioxidants, stabilizers, ultraviolet absorbers, lubricants, processing aids, An antistatic agent, a colorant, an impact resistance aid, a foaming agent, a filler, a matting agent, and the like may be blended.

  Among the above additives, polyhydric alcohol is preferably used as the plasticizer, and specific examples thereof include ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, trimethylolpropane. Etc. These plasticizers can be used alone or in combination of two or more. Glycerin is preferred from the viewpoints of volatility and plasticity.

Hereinafter, the manufacturing method of the resin composition of this invention is demonstrated.
In order to disperse zinc antimonate in the resin composition with an average particle size of 60 nm or less, preferably 50 nm or less, it is preferable to prepare in advance a dispersion in which zinc antimonate is finely dispersed. The dispersion can be obtained as a commercially available sol, but in that state, primary particles are aggregated, and the average particle diameter is often around 100 nm or more. Therefore, in order to finally disperse the zinc antimonate in the resin composition with an average particle size of 60 nm or less, preferably 50 nm or less, it is preferable to perform an operation of mechanically wet-grinding the dispersion.

  As a device for mechanically grinding and finely dispersing zinc antimonate in a dispersion liquid, any device that can grind and disperse particles of zinc antimonate in which primary particles are aggregated is particularly limited. However, for example, a sand mill, a ball mill, a jet mill, a homogenizer, an attritor, a paint shaker, a high-speed stirrer, an ultrasonic disperser, a bead mill and the like can be mentioned. A bead mill is preferable in order to achieve a fine average particle diameter efficiently. When using a bead mill, processing is performed using beads at the time of pulverization, and the finer the beads, the more efficiently the particles can be made. The diameter of the beads to be used is preferably 0.2 mmφ or less, more preferably 0.1 mmφ or less, and even more preferably 0.05 mmφ or less. When the diameter of the beads is larger than 0.2 mmφ, aggregates of zinc antimonate remain in the resulting dispersion, and the target zinc antimonate cannot be refined, and high transparency is required. In some cases, use may be limited. The average particle diameter of zinc antimonate in the thus obtained finely divided dispersion is 60 nm or less, preferably 50 nm or less, and more preferably 40 nm or less. If it exceeds 60 nm, there are many secondary aggregates in which primary particles are aggregated in the finally obtained resin composition, so light is scattered under visible light, haze increases, and high transparency is required. Use may be limited in certain applications.

  Next, the dispersion liquid after the above-mentioned miniaturization is mixed with PVA. Although it does not specifically limit as a method to mix, The dispersion liquid after refinement | miniaturization and PVA may be mixed by melt-kneading, and may be mixed after melt | dissolving PVA in a solvent. As a kneading method, for example, a known kneader such as a single screw extruder, a twin screw extruder, a brabender, an open roll, a kneader, or the like can be used. Examples of the PVA solvent include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylolpropane, ethylenediamine, diethylenetriamine, and the like. 1 type or 2 types or more of these can be used. Among these, water is preferably used from the viewpoint of load on the environment and recoverability.

  The resin composition of the present invention is produced by removing the solvent from the above mixture. At this time, it is also possible to directly produce molded articles such as films and sheets from the kneaded product. The method for producing such a molded body is not particularly limited, and may be produced by any conventionally known method as long as the thickness and width after film formation are as uniform as possible. A gel film forming method, a dry casting film forming method, an extrusion film forming method, a method using a combination of these, and the like can be employed. Among these production methods, the extrusion film forming method is preferable because a molded body having a uniform film thickness and width and good physical properties can be obtained. The obtained molded product is subjected to drying or heat treatment as necessary. When the molded product is a sheet, the thickness is generally about 10 to 200 μm, and preferably about 20 to 150 μm.

  The resin composition of the present invention has a visible light transmittance in a wavelength region of 380 to 780 nm measured in accordance with JIS R3106 of 70% or more, and a solar transmittance in a wavelength region of 300 nm to 2500 nm is 80% or less, And it is preferable that the haze measured according to JIS K7105 is 4.0% or less. The resin composition has a visible light transmittance of 70% or more in a wavelength region of 380 to 780 nm and a solar radiation transmittance of 80% or less in a wavelength region of 300 nm to 2500 nm. A shielding effect can be obtained. Here, the visible light transmittance is preferably 5% or more higher than the solar radiation transmittance. Moreover, favorable transparency can be acquired because the haze of a resin composition is 4.0% or less.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by an Example. In the following Examples and Comparative Examples, each physical property was measured or calculated as follows.

[Dispersed particle size of zinc antimonate in dispersion]
Using a dynamic light scattering photometer “DLS-7000” manufactured by Otsuka Electronics Co., Ltd., using a He—Ne laser (632.8 nm), the average particle size in the dispersion at a measurement angle of 90 ° and 20 ° C. It was measured. Using the obtained measurement results, the average particle diameter (nm) was calculated according to the cumulant method.

[Visible light transmittance and solar radiation transmittance]
Using a spectrophotometer “SolidSpec-3700” manufactured by Shimadzu Corporation, the transmittance in a wavelength region of 280 to 2500 nm was measured for the formed article. Then, according to JIS R3106, obtained visible light transmittance up 380~780nm (percent). Also, it was obtained solar transmittance to 300~2500nm using heavy valence coefficient of JIS R3106 described (%).

[Haze]
Using a turbidimeter “NDH-5000” manufactured by Nippon Denshoku Industries Co., Ltd., the haze (%) was measured according to JIS K7105.

[Preparation of dispersion]
A 60% by weight methanol dispersion of zinc antimonate (chemical composition ratio: ZnSb ₂ O ₆ ) (“CX-Z693M-F” manufactured by Nissan Chemical Co., Ltd.) was wet using a bead mill (diameter of beads used: 0.05 mmφ). and pulverized to obtain a dispersion of zinc antimonate was dispersed in 37nm and (b1).

[Production and evaluation of resin moldings]
A 10% by weight PVA aqueous solution (b2) having an average degree of polymerization of 1700 and a degree of saponification of 98.5 mol% was prepared. It mixed and dried on the metal roll of 60 degreeC, and the molded object (sheet | seat) whose thickness is 100 micrometers was obtained. The results of evaluating the obtained sheet are shown in Table 1.

  A sample was prepared in the same manner as in Example 1 except that zinc antimonate was mixed at 1 part by weight with respect to 100 parts by weight of PVA. Table 1 shows the results of evaluation of the obtained molded body (sheet).

Comparative Example 1
A sample was prepared in the same manner as in Example 1 except that the dispersion liquid (b1) was not added. Table 1 shows the results of evaluation of the obtained molded body (sheet).

Comparative Example 2
A sample was prepared in the same manner as in Example 1 except that the pulverization treatment was not performed on the methanol dispersion of zinc antimonate. Table 1 shows the results of evaluation of the obtained molded body (sheet).

  From the results shown in Table 1, the molded articles of the present invention (Examples 1 and 2) have high visible light transmittance, while keeping solar radiation transmittance low, almost no haze, and high transparency and heat ray shielding. It turns out that it has sex. On the other hand, when zinc antimonate is not included as in Comparative Example 1, the obtained molded article has high solar transmittance, and the heat ray shielding performance is not sufficient. When the dispersion containing zinc antimonate was not pulverized as in Comparative Example 2, the haze was high and the transparency was not sufficient.

Claims (4)

  A resin composition comprising polyvinyl alcohol and zinc antimonate, wherein the zinc antimonate is dispersed in the resin composition with an average particle size of 60 nm or less.   Haze measured in accordance with JIS K7105 with visible light transmittance in the wavelength region of 380 to 780 nm of 70% or more measured in accordance with JIS R3106, solar radiation transmittance in the wavelength region of 300 nm to 2500 nm of 80% or less. The resin composition according to claim 1, wherein is 4.0 or less.   The method for producing a resin composition according to claim 1, comprising a step of subjecting the zinc antimonate dispersion to wet pulverization and then mixing with polyvinyl alcohol.   The molded object which consists of a resin composition of Claim 1 or 2.